Spring device



Feb. 17, 1942. 1.. H. MATTHIAS SPRING DEVICE 2 Sheets-Sheet 1 Filed March 27, 1939 IN VEN TOR. Inwv H. MA TTHIAS M J W A TTORNEY F65. 17} 1942. L.H. MATTHIAS ,3

' sriune nsvrcg-z Filed latch 27, 1939 2' Sheets-Shut 2 INVENTOR.

.lmwfvimrmms BY wzmvx AT EY excessive friction of the coil spring,

Patented set. 17,- 1942 SPRING na'vrca Lynn 8. Matthias, Shorewood, Wis assignor to Allen-Bradley mm. corporation of Wisconsin Milwaukee, Wis; a

Application March 27, 1939, Serial No. 264,428

.4 Claims.

This invention relates in general to an improved support for to a support for a coil spring used as a spring return device on an electromagnetic switch Electromagnetic switches depend primarily upon the weight of the armature with its attached parts and the force of the contact springs to return the movable switch part to its normally open position; p

In addition to this weight and contact spring force there is added in some instances to secure a more definite and precise opening of the mov-. able part, a return spring.

Heretoi'ore difllculty was experienced in the mounting of a torsion spring in that the movement of the spring on its support incurred a frictional force which caused indefinite opening and a wear of parts.

An object of this invention is to provide an improved i'orm of between the rotatable end turns of the spring and its support is eliminated.

A further object 01 this invention is to provide a support for a coil spring in which one end of the coil spring is restrained from rotating relative to a mounting spindle and the other-end which end is free to rotate relative to the spindle, is provided with a bearing and shoulder opposing radial thrust and end thrust 'of the spring. Thus the rotatable end 1 of the coil spring rotates on the spindle free of restraint by the attenuated rotary motion of the turns of the coil spring that do not have bearing contact with therotatable bearing and shoulder.

A iurther object of this invention is the utilization of the new and improved coil spring support as a return device for the armature of an electromagnetic switch.

Referring to the attached drawings,

Figures 1 and 2 show a front and side elevation respectively of a magnetic switch in the normally open position;

Figure 3 is a view in perspective of the return spring mechanism; 7

Figure 4 is an exploded view of the return spring mechanism shown in Figure 3; and

Figure 5 is an enlarged view ct an assembly of the return spring mechanism.

The magnetic switch shown in detail in Figures 1 and 2 includes 'a back supporting frame I to which is attached an electromagnet 3, consisting of fieldpiecel, armature 5, coil 6, stationand armature return ary contactsupports 1 mechanism 24. There is also attached to the fieldpiece 4 afront supporting frame 2 which in coil springs and in particular" coil spring support in which conjunction with the back" supporting frame I provides the complete support for stationary contact supports '!1.

The switch operates in a vertical position as shown. The iieldpiece 4 has a lower rectangular opening I3 for the armature 5, an upper rectangular opening I 4 for the switch operating member 40 and an opening 4| for the switch coil 3. The switch coil 6 is placed in opening 4| and an armature guide I! is inserted through openingl3 The-armature guide I! is held in place in the fleldpiec 4 by means of pin l6 that is attached to the fieldpiece 4 and which passes through slotin the fieldpiece 4 and opening 42 in the II that is formed in switch-operating member 40.

The armature 5 is placed in the guide I! from the bottom with the switch operating member 40 projecting through openingl4.

"Rigidly connected to the switch operating member '40 is the cross bar [8 that carries the movable contact members 2l--2| each having attached thereto, two contacts 22-22.

Each contact member 2| is spring mounted by means of guide post I! and spring 20.

The stationary contact supports 1-! carry the stationary contact members 88 88 each having attached thereto a terminal i0 and a conto its normal position tact 3.

In order to assist the armature 5 to return as shown in Figures 1 and 2 an additional downward force is applied by means of the spring return mechanism 24. mechanism which embodies the invention is shown in detail in Figures 3, 4 and 5.

A spindle 25, having formed thereon a rivet portion 26, a bearing seat 21, a shoulder 28, and cotter pin hole 29, is attached to the back supporting frame I by means of riveting 26. A helical coil spring 30 is placed on spindle with its end 3| in a hole 31 of back supporting frame I. Bearing. 33 is placed on bearing seat 21 and inside of coil spring so that the shoulder 34 of bearing "contacts the free end turn of the coil spring 30. A washer 35 and a cotter pin 36 are used to securely hold the coil spring 30 and bearing 33 in place. The movable end 32 of coil spring 30 fits within hole 23 in armature 5.

- It is to be noted that t e outside diameter of spindle 25 and the outside diameter of bearing 33 are slightly of spring 30.

smaller than the inside diameter The coil spring 30 as formed is so designed that it is preloaded in the normal position as shown in Figures 1 and 2. By providing various positions such as holes 31- and 31' and the shoulder 39 formed by hole 38,-three possible positions for the stationary end 3|-of coil spring 30 are.

provided thus ofiering control over the force applied by the spring mechanism without altering the design of the spring.

The magnetic switch operates in the usual well known manner. As shown in Figures 1 and Zthe The motion of the armature 5' is transmitted directly to the movable contact structure placing movable contacts 22-42-22-22 in con tact with stationary contacts 9-9 -89.

In the closed or energized position there are three forces directed to lower the armature 5;

the weight of the armature and attached parts;

the contact springs and the armature return mechanism 24. When the switch coil 5 is deenergized these forces operate to return the armature and movable contacts to the open position.

In the case where a magnetic switch is equipped withhormally closed contacts the return spring mechanism is of special importance. In such a switch the stationary contacts 9 are below the movable contacts 22 and spring. is mounted on post I9 above rnovable contact member 2|. With the magnetic coil 6 de-energized the engagement of contacts 9 and 22 is then caused by the weight of armature and attached parts plus the force exerted by the return spring 30.

In the operation of the spring return mechanism, the bearing 33 and shoulder 34 are free end of the spindle mounting the bearing; said to rotate on the bearing seat 21 thus providing a surface for supporting the free end of the coil 34 provide for the complete support of the ro-' tatable end of the coil spring. The bearing and shoulder oppose radial thrust and end thrust imparted to the coil spring 30 by the armature 5 upon movements from one position to another.

The free end of the coil spring is thus freeto wind and unwind around its supporting spindle free of restraint by the attenuated rotary motionof those turns of the spring that do not have bearing contact with hearing 33.

The-coil spring 30, assembled as in the switch device, will have the first turn or so, adjacent end- 32 contacting on lower surface of bearing 33, as clearly shown in Figure 5.

' -f,: I I of spring and supporting surface would-be excessive and prevent proper operation ofthe spring return device.

From the foregoing description taken in connection with the accompanying drawings, it will be readily apparent to those skilled in the art that this invention provides a simple and efli-,

cient-manner of supporting a spring, which support in no wise gives rise to objectionable friction.

What I claim as my invention is:

1. The combination of an electromagnet having a base and a movable armature with a spring return device for said armature, comprising a helical coil spring, a spindle and a bearing with a shoulder integral therewith; one end of the spindle being mounted on the base and the other coil spring disposed concentrically on the spindle with one end of the spring attached to the base and restrained from rotating relatively to the spindle; the other end of said coil spring attached to the armature whereby upon movement of the armature said second mentioned end rotates rel-' atively to the spindle; said bearing being rotatable on the spindle and extending sufliciently inside the turns at the second mentioned end of the coil spring to oppose radial thrust and end thrust of said second mentioned end but not far enough to come into contact with the remaining turns of the spring, whereby, said bearing and shoulder turn with and support the end of the spring attached to. the armature free of restraint by the turns of the spring between the bearing, and the base.

2. A spring -retum device for an electro mounted on the base and the other end of the spindle mounting the bearing; said cnil spring disposed concentrically on the spindle with one end of the spring attached to the base and restrained from rotating relative to the spindle; the other end of said coil spring having means coupling it with the armature whereby upon straight line motion of said armature said second mentioned end rotates relative to the spindle:'

said bearing being rotatable on the spindle with said shoulder opposing end thrust of said second With the diameters of the spring, bearing and spindle properly-proportioned and with proper clearance between turns of spring, the force applied to the end turn of spring will be substantiallytransmitted to the remaining turns of spring with little loss due to friction.

It is also to be noted that the disclosed structure minimizes wear by the end turn of the spring against its supporting surface, which wear if allowed to continue might eventually bring into contact with the supporting surface the secend and third-turns of spring. Under such a 'wearing condition the friction force between turns mentioned end, and said bearing extending far enough within suflicient turns at the end of the spring attached to the armature to oppose radial thrust thereof but not far enough to come into contact with the remaining turns of the spring, whereby, said bearing and shoulder turn with and support the end of the spring attached to the armature free of restraint by the turns of the Spring having less relative motion with respect to the spindle than the end turns in contact with said bearing. y

3. In a coil spring support the combination of a base member, a spindle attached to the base member, a coil spring having a plurality of turns disposed concentrically on the spindle with one end of the spring attached to the base and the other end free to rotate relative to the spindle, and a bearing with a shoulder integral therewith rotatably mounted on the spindle with the hearing extending sufliciently inside the turns at the free end of the coil spring to maintain the free end of said coil spring concentric with said spin- I 4. In a coil spring support the combination of a base me' her, a spindle attached to the base member, elical cofi spring having a plurality or turns d1e and to oppose radial thrust otthe Ireeend 'but not'f'ar enough to come into contactwwith the remaining turns of the spring, and with the shoulder opposing the end thrust of the free end, whereby, upon rotary motionoi the free end of the coil spring relativeitofthe spindle the bear- 7 ing supports and'rotates with saidf ree end sub- 1. stantially unrestrained by the turns of the spring a having attenuated rotary motion. spring relative to the; spindle the bearingand' a disposed concentrioallyon the sniliiclle with one',end otthe spring attached to thebase mounted 'on the spindle with the bearing extending inside and having bearing'conta'ct with only a limited number of turns contiguous with the free endoi' the coil spring and with-the shoulder opposing end thrust of-the tree end, whereby, upon rotary motion of the free end of the coil shoulder support and rotate with said free end with the bearing unrestrained by the attenuated rotary motion of ,the .remainingturns.

LYNN H. MA'ITHIAS.

and the other end tree to rotate "relutive to the spindle,.and a bearing-and shoulder rota'tably 

